I am using Windows 10 on HP EliteBook 850 G4. In last few months, sometimes there occurs a hang of the system. Firefox shows "Does not respond", explorer.exe (task panel) doesn't respond, but I can for example minimize some windows and change focus to window on second screen. Even keyboard shortcuts for Task manager or Ctr+Alt+Del do not work.

In half a minute, everythink returns to normal and works as nothing was wrong. But in a few minutes, the issue is back. Sometimer reboot helps, but just for a few hours. Some days this doesn't occur at all. I haven't found any shedule in it.

A few times I happened to have opened Task manager window and every time when this hang occures, the service "Remote procedure call (RPC) jumps up to first place with 30% CPU use. But the processor is still not used more than 50%. I tried to google this symptoms and have only found one message with suggestion to disable OneDrive. Today morning whed the hang occured again, I closed OneDrive (right-click and "Exit"), but in a few minutes, the hang returned. I have no way to test if the issue is solved, the hang uccurs "randomly".

Is there any way to find, which process uses RPC service at the moment? Maybe Wireshark can help, but I don't know the correct filter option to find this communication.

I have tested the OS for malware and so on with McAfee (company licence), Malwarebytes and even Microsoft Safety Scanner with no positive result.


Only error found in event log was: The machine-default permission settings do not grant Local Activation permission for the COM Server application with CLSID... where CLSID points to RuntimeBroker.exe
I will check again when the hang occurs again, if this error log correlates

  • 1
    It's possible the RPC service is a victim, not the cause. Anything interesting being logged in the Event logs? Dec 6 '17 at 13:00
  • Totaly forget about event log, thank you. Please see the update. I will check again when the hang occurs.
    – DangeMask
    Dec 6 '17 at 13:28
  • If you have an idea of when the last hang occurred, you can look in the log now for unusual events. Using the custom Administrative Events view will show all error/warning events. Dec 6 '17 at 13:29
  • To be honnest, I haven't write down the exact time of the issue. But the error written in Update 1 occured few times today, which somehow correlates with the hangs. I'm just not 100% sure.
    – DangeMask
    Dec 6 '17 at 13:41
  • 5 mnutes ago, the hang occured again. And nothing new appeared in Event log :-(
    – DangeMask
    Dec 6 '17 at 14:20

I got my solution from the HP forum (link https://h30434.www3.hp.com/t5/Notebook-Audio/Flow-exe-spikes-to-20-CPU-and-causes-sporadic-windows-freeze/td-p/6483020/page/2):

Rename Flow.exe file "C:\Program Files\CONEXANT\Flow\Flow.exe" to something else (Flow_dontstart.exe for example).

Background: It seems that the Flow-Tool from the Conexant Bang & Olufsen audio driver is causing the mess. From the description on the forum it checks certain programs to derive the best audio mode from it. When it tries to read information form Firefox it causes the OS to freeze up.

Since I renamed flow.exe my Elitebook 840 G5 works fine.

If you have the Bang & Olufsen audio hardware, this should work for you.

And: Don't try to remove the Bang & Olufsen software via "Apps & features". It will come back automatically.

  • Thank you, this is first forum I see where someone suggested real solution. I tried the rename solution and will give it a week to be sure (the lags don't come regularly). If everything would work, I will amrk your answer as a solution.
    – DangeMask
    Nov 20 '18 at 11:25
  • Hi @DangeMask, hope the fix worked for you. If yes it would be great if you mark the solution. Dec 4 '18 at 9:09
  • 2
    Looks like it works. No hangs for two weeks. Thank you very much
    – DangeMask
    Dec 4 '18 at 12:54
  • Updated Windows to 1809 yesterday and got the same issues today morning. So I applied the same solution and we will see :-)
    – DangeMask
    Apr 12 '19 at 6:06
  • 2
    Hi @DangeMask, it is normal that you get the same issues now, because a Windows 10 "Update" is not really an update, technically speaking. Behind the scenes you get a complete new Windows install, including driver-installs. After the install Windows moves your files to the new install so it appears to be an update. Applying the same solution should work. Good luck! :-) Apr 12 '19 at 10:10

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